feat(server): record set releases and the nests they made

Releasing a drawing set makes one nest per material group, so a kit run
spans several nests. The server now records which set revision was
released, the multiplier and the nests it made, so a run can be tracked
across its nests and a nest can say where it came from.

The client uploads every nest first and posts the release last: a failure
part-way leaves ordinary nests and no release, never a release pointing at
missing nests. For the same reason a release is accepted for an older set
revision or an archived set, since the nests already exist by then. The
release id is client-allocated and a nest belongs to at most one release,
so a retried post gets 409 with the release that already holds it.

Releases are append-only and read joined to each nest's current metadata,
so status and deletion are always current. The tables join schema v7, as
the set tables have not shipped yet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

OpenNest.Server.Tests/DrawingLibraryDatabaseTests.cs

@@ -236,6 +236,7 @@ public sealed class DrawingLibraryDatabaseTests
         }
 
         Execute(path, """
+            DROP TABLE set_release_nests; DROP TABLE set_releases;
             DROP TABLE drawing_set_members; DROP TABLE drawing_sets; DROP TABLE drawing_set_revisions;
             DROP TABLE drawing_revisions; DROP TABLE drawings; DROP TABLE drawing_packages; PRAGMA user_version=3;
             """);